Programming / configuring PXI1033 for trigger signals between installed cards with NIDAQ

[Kai42]

Hello,
for my application, time critical analoge data aquisition needs to be initiated by a trigger pulse coming from a very accurate oscillator.
I need assistance with configuring the control software (C, with the NIDAQ drivers; not Labview) to
1) providing those repetitive trigger signals from a timing card to all other cards
2) configure the ADC cards to perform measurements every time such a trigger pulse is received.

Test equipment:
NI-PXI 1033 with the following cards:
NI-PXI 6608 (Timing Card) (slot 2)
NI-PXI 4472B (ADC input cards) (other slots)

Detailed description:
All cards are installed in the NI-PXI-1033 data aquisition rack which is connected to / controlled by a computer using C, not Labview.
1) The timing card contains an 80 MHz oscillator / internal counter of oscillator events.
This oscillator / counter shall be used for sending a trigger signal every 0.1 ms or 0.05 ms to the backplane, that is to all slots = all installed cards in the PXI-1033 data aquisition rack.

2)The PXI4472 ADC cards shall be configured for listening for that trigger signal and then perform a single measurement simultaneously on all 8 channels for an integration time of xy microseconds and then wait for the next trigger signal.

Any advice on useful C commands is appreciated, ideally a link to some similar project / code.

But even some exemplary Labview command sequence could be useful due to some similarity between function names...

Best regards,

Kai

[CorinneDoppmann]

Hi

Please have a look at the provided DAQmx Examples for C:

Where Are NI-DAQmx Examples Installed in Windows? - National Instruments
https://www.ni.com/en/support/documentation/supplemental/18/ni-daqmx-example-locations-for-labview-a...

Especially this example should be interesting with an external digital trigger:

C:\Users\Public\Documents\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage\Acq-Int Clk-Dig Start Ref

You will need to configure a finite acquisition task which is retriggerable.

Check out the Retriggerable function here:

Start >> More >> Retriggerable - NI-DAQmx C Reference Help - National Instruments
https://www.ni.com/docs/en-US/bundle/ni-daqmx-c-api-ref/page/mxcprop/attr190f.html

Let me know if you need any more help or have any further questions.

Best regards,

[CorinneDoppmann]

Hi

I forgot to talk about the fact that you want to route the clock from one PXI card to the other.

Please have a look at the following ressources:

Synchronization Explained - National Instruments
https://www.ni.com/en/support/documentation/supplemental/10/synchronization-explained.html

Design Considerations for PXI Timing and Synchronizations - Discussion Forums - National Instruments
https://forums.ni.com/t5/User-Group-Resource-Center/Design-Considerations-for-PXI-Timing-and-Synchro...

Timing and Synchronization Features of NI-DAQmx - National Instruments
https://www.ni.com/en/support/documentation/supplemental/06/timing-and-synchronization-features-of-n...

Most of the tutorials are based on LabVIEW. But the principles can be transfered to C pretty easily. The functions should have similar names.

You can also have a look at the DAQmx C Reference:
https://www.ni.com/docs/en-US/bundle/ni-daqmx-c-api-ref/page/cdaqmx/help_file_title.html

Best regards,